Apparatus and method for concentrating hydrogen isotopes

ABSTRACT

In an embodiment, a method of concentrating a hydrogen isotope, comprises delivering a fluid comprising the hydrogen isotope to be concentrated and an additional gas other than then hydrogen isotope to an anode of an electrochemical cell comprising a hydron exchange membrane comprising hydrons of the hydrogen isotope, and also comprising said anode on a first side of the hydron exchange membrane, a cathode on a second side of the hydron exchange membrane, and an electrical circuit connection between the anode and the cathode; removing a first stream in fluid communication with the cathode, the first stream comprising concentrated hydrogen isotope; and removing a second stream in fluid communication with the anode, comprising the additional gas delivered to the anode depleted of the hydrogen isotope.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a divisional application of U.S. applicationSer. No. 15/701,089 filed on Sep. 11, 2017, which claims priority toU.S. Provisional Patent Application Ser. No. 62/385,787, filed Sep. 9,2016, the disclosures of which are incorporated herein by reference intheir entirety.

BACKGROUND

Isotopes of hydrogen, including deuterium and tritium, are useful in awide variety of commercial and industrial processes such as toadvantageously improve the properties of a wide variety of productsincluding food and nutrition products, agricultural products,semiconductors, fiber optics, optoelectronics, and others. While thereis a strong desire to include these isotopes in numerous products andprocesses, such use has generally been hindered by the relative scarcityof the isotopes.

As such, there is a need for new processes and equipment to recyclethese isotopes or otherwise purify fluids containing these isotopes inhigh purity so that they can be used or re-used in the processes inwhich they are employed.

BRIEF DESCRIPTION

An electrochemical hydrogen isotope concentrating apparatus isdisclosed. The apparatus includes an inlet stream comprising thehydrogen isotope to be concentrated. The apparatus also includes anelectrochemical cell comprising a hydron exchange membrane comprisinghydrons of the hydrogen isotope, an anode on a first side of the hydronexchange membrane in fluid communication with the inlet stream, acathode on a second side of the hydron exchange membrane, and anelectrical circuit connection between the anode and the cathode. Theapparatus further includes two outlet streams: a first outlet stream influid communication with the cathode, the first outlet stream comprisingconcentrated hydrogen isotope, and a second outlet stream in fluidcommunication with the anode, comprising fluid from the inlet streamdepleted of the hydrogen isotope.

A process by which high purity hydrogen isotope products are produced isdisclosed. The process comprises an electrochemical membrane process inwhich all conventional water containing components are pre-processedusing a heavy water containing the isotope of hydrogen.

A method of concentrating an isotope of hydrogen is also disclosed. Themethod comprises delivering a fluid comprising the hydrogen isotope tobe concentrated to an anode of an electrochemical cell comprising ahydron exchange membrane comprising hydrons of the hydrogen isotope, theanode on a first side of the hydron exchange membrane, a cathode on asecond side of the hydron exchange membrane, and an electrical circuitconnection between the anode and the cathode. A first stream in fluidcommunication with the cathode is removed, the first stream comprisingconcentrated hydrogen isotope. A second stream in fluid communicationwith the anode is removed, the second stream comprising fluid deliveredto the anode depleted of the hydrogen isotope.

In some embodiments, water comprising the hydrogen isotope can bedelivered to the hydron exchange membrane.

In some embodiments, the hydron exchange membrane can be contacted withwater comprising the hydrogen isotope prior to delivering the fluid tobe concentrated to the anode.

In any one or combination of the foregoing embodiments, water comprisingthe hydrogen isotope can be delivered to the hydron exchange membranesimultaneous to delivering the fluid to be concentrated to the anode.

In any one or combination of the foregoing embodiments, the hydronexchange membrane can comprise a hydrogen exchange support material andwater comprising the hydrogen isotope.

In any one or combination of the foregoing embodiments, the water cancomprise a predetermined atomic fraction of the hydrogen isotope.

In any one or combination of the foregoing embodiments, thepredetermined atomic fraction of the isotope can be configured toproduce a target hydrogen isotope purity of the first outlet stream.

In any one or combination of the foregoing embodiments, the apparatuscan further comprise a source of water comprising the hydrogen isotopein fluid communication with the hydron exchange membrane.

In some embodiments, the water source can comprise a liquid water flowloop in fluid communication with the hydron exchange membrane.

In some embodiments, the water source can comprise a humidifier in fluidcommunication with the inlet stream.

In any one or combination of the foregoing embodiments, the hydronexchange membrane can comprise an ionomer.

In any one or combination of the foregoing embodiments, the ionomer cancomprise a fluoropolymer comprising sulfonate groups.

In any one or combination of the foregoing embodiments, the apparatuscan further comprise a dehumidifier in fluid communication with thefirst outlet stream.

In any one or combination of the foregoing embodiments, the hydrogenisotope can comprise deuterium.

In any one or combination of the foregoing embodiments, the hydrogenisotope can comprise tritium.

In any one or combination of the foregoing embodiments, the apparatuscan comprise a stack of the electrochemical cells.

In any one or combination of the foregoing embodiments, the first outletstream can be electrochemically compressed to a pressure greater thanatmospheric pressure.

In any one or combination of the foregoing embodiments, water comprisingthe hydrogen isotope is recycled or recovered.

The above features and advantages and other features and advantages ofthe invention are readily apparent from the following detaileddescription of the invention when taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, advantages and details appear, by way of example only,in the following detailed description of embodiments, the detaileddescription referring to the drawings in which:

FIG. 1 is a schematic illustration of a hydrogen concentratingapparatus;

FIG. 2 is a schematic illustration of a hydrogen concentrating apparatuswith liquid water comprising a hydrogen isotope supplied to a hydronexchange membrane; and

FIG. 3 is schematic illustration of a hydrogen concentrating apparatuswith water vapor comprising a hydrogen isotope supplied to a hydronexchange membrane.

DETAILED DESCRIPTION

A detailed description of non-limiting example embodiments of apparatus,components, systems, and/or methods is set forth below. Correspondingreference numerals may be used throughout multiple drawings to indicatelike or corresponding parts and features.

Referring now to FIG. 1, an example embodiment is shown of a hydrogenisotope concentrating apparatus 10 is shown. As shown in FIG. 1, theapparatus 10 includes an electrochemical cell comprising a hydronexchange membrane 12 with anode 14 and cathode 16 on opposite sidesthereof, and an electrical circuit 18 connecting the anode and cathode.The hydron exchange membrane 12 with anode 14 and cathode 16 can also bereferred to as a membrane electrode assembly or MEA. Other componentscan be associated with the MEA, such as anode-side and cathode-side flowfield structures (not shown) that provide fluid flow paths for processliquids or gases. These structures are typically disposed distal fromthe MEA, with the MEA and flow field structures mounted in a frameassembly (not shown), to provide space for fluid flow in contact withthe MEA. A power supply or other electronic component (e.g., anelectronic control unit or ECU) with integrated power supply 20 isconnected to the electrical circuit 18 to provide electrical power orcontrol to the electrochemical cell.

In operation, the electrochemical cell receives an inlet stream 22comprising the hydrogen isotope to be concentrated (^(n)H₂, where n isas described hereinabove). In some embodiments, the inlet stream 22 cancomprise at least one other gas component (e.g., nitrogen, argon, carbonmonoxide, carbon dioxide; identified in FIG. 1 as nitrogen solely forease of reference) such as in a spent process gas recycle stream. Insome embodiments, the inlet stream can be a hydrogen isotope supplystream containing impurities to be removed (i.e., increasing theconcentration of the hydrogen isotope). In some embodiments, the inletstream can contain pure hydrogen isotope or a hydrogen isotope thatalready meets purity specifications, and the electrochemical cell isused to provide the hydrogen isotope at a higher pressure (i.e., anotherform of increasing the hydrogen isotope concentration). Theelectrochemical cell operates as a separator in which the current fromthe power source 20 applied to the electrodes (anode 14 and cathode 16)drives hydrogen ions (hydrons) across the hydron exchange membrane 12from the anode side to the cathode side while other component(s) in theinlet stream 22 remain on the anode side. Hydrogen is ionized at theanode 14, with liberated electrons acquired by the electrical circuit18. The ionized hydrogen passes through the hydron exchange membrane 12to the cathode side, where it combines with electrons at the cathode 16to the hydrogen isotope to form outlet stream 24. The hydrogen-depletedgas on the anode side forms outlet stream 26, which can, depending onits identity/properties, be discharge, fully or partially recycled backto inlet stream 16, or subjected to further processing, recycling, orre-use is discharged as outlet stream 26.

Anode 14 and cathode 16 can be fabricated from catalytic materialssuitable for performing the needed electrochemical reaction (e.g., thedissociation of hydrogen gas). Suitable catalytic materials include, butare not limited to, platinum, palladium, rhodium, carbon, gold,tantalum, tungsten, ruthenium, iridium, osmium, alloys thereof, and thelike, as well as combinations of the foregoing materials. Anode 14 andcathode 16 are positioned adjacent to, and preferably in contact withthe hydron exchange membrane 12, and can be defined by structurescomprising discrete catalytic particles adsorbed onto a poroussubstrate. Adhesion of the catalytic particles onto a substrate may beby any method including, but not limited to, spraying, dipping,painting, imbibing, vapor depositing, or combinations of the foregoingmethods, and the like. Alternately, the catalytic particles may bedeposited directly onto opposing sides of proton exchange membrane 12 oronto support members (not shown).

The hydron exchange membrane can be selected from materials that canaccommodate hydron exchange or transfer through the membrane whileavoiding passage through the membrane of other atomic or molecularspecies such as nitrogen or oxygen. In some embodiments, hydron exchangematerials can contain ionic molecular groups such as sulfonate groupsthat allow for transfer or exchange of hydrons between proximatesulfonate groups in the membrane to allow for transfer or exchange ofhydrons through the membrane during operation. Examples of hydronexchange membranes can include ionomers such as sulfonatedfluoropolymers (i.e., perfluoropolymers in which all hydrogens in themolecule are replaced by fluorine atoms) such as NAFION polymers sold byDuPont. Other hydron exchange materials can include materials can usedifferent ionomers such as those with polyaromatic polymer backbonestructures or partially fluorinated polymers.

As mentioned above, the hydron exchange membrane comprises hydrons ofthe hydrogen isotope to be concentrated. In some embodiments, the hydronexchange membrane can include such isotope(s) at an atomic concentrationthat is higher than the concentration of the isotope(s) found innaturally occurring hydrogen. In some embodiments, the hydron exchangemembrane can include such isotope(s) at an atomic concentration that isgreater than or equal to the concentration of the isotope(s) found inthe inlet stream to be concentrated. In some specific exampleembodiments, the hydron exchange membrane can include deuterons at anatomic percentage of at least 50%, or at least 90%, or at least 99%, orat least 99.9%, or at least 99.99%, based on the total hydrogen contentof the hydron exchange membrane. As used herein, the term “hydrogenisotope” means any hydrogen isotope, and the apparatus and methodsdisclosed herein can be used with any known isotope of hydrogen. As apractical matter, the only known stable isotopes of hydrogen aremonohydrogen under normal conditions (also referred to herein as “¹H” or“H”), deuterium (also referred to herein as “²H” or “D”), and tritium(also referred to herein as “³H” or “T”), so under normal operatingconditions, the hydrogen isotope to be concentrated can be monohydrogen,deuterium, or tritium. In some embodiments, the hydrogen isotope to beconcentrated is deuterium. In some embodiments, the hydrogen isotope tobe concentrated is tritium. Hydrogen isotopes capable of beingconcentrated under normal operating conditions can also be referred tocollectively as “^(n)H”, where n is 1, 2, or 3, or in some embodiments nis 1 or 2, or in some embodiments n is 2, or in some embodiments n is 3.

In some embodiments, the hydrogen isotope to be concentrated can bedisposed in the hydron exchange membrane by pre-treating the hydronexchange membrane or material out of which the membrane is to be formedwith isotopic water. As used herein, the term “isotopic water” meanswater that has a higher concentration of the hydrogen isotope to beconcentrated than occurring naturally in water. The pre-treatmentprocess can occur during or after fabrication of the hydron exchangematerial. In some embodiments, isotopic water can be used to ionizeionic groups (e.g., reacting water with a sulfonyl fluoride to formsulfonate groups). However, the handling and processing of isotopicwater in such strongly acidic reaction conditions can presentdifficulties. Accordingly, in some embodiments, the hydron exchangematerial can be contacted with isotopic water after ionization byregular water, allowing for hydrons of the hydrogen isotope to beconcentrated to displace hydrons of different isotopes such asmonohydrogen from the molecules of the hydron exchange material. Thiscan be done regardless of whether the polymer is in the form of pelletsor already fabricated into membrane sheets. The pre-treatment involvesrepeatedly soaking the hydron exchange material in isotopic water, ifnecessary with repeat soakings in fresh isotopic water until the isotopelevels in the hydron exchange material reach the desired levels. Soakingat elevated temperature (e.g., between 25° C. and 100° C.) may beperformed as well. If the hydron exchange membrane has multiplecomponents or layers, each of the components or layers can bepre-treated as well. For example, small strands of ionomer can beextended into the electrode layer, and this material can also be treatedwith isotopic water.

Conventional proton exchange membranes (PEM) contain protons that areionically bound to anionic groups such as sulfonates. The strength ofthese ionic bonds can be overcome under the influence of the protonsbeing electrochemically urged from the anode to the cathode so thatprotons transfer between proximate ionic groups. Accordingly, as protonsenter the proton exchange membrane from the anode, different protons,which had immediately prior been disposed in the membrane, emerge fromthe membrane to form hydrogen gas at the cathode. In the case ofelectrolytic concentration of hydrogen isotopes having a differentdistribution of isotopes than found in nature, conventional protonexchange membranes can contaminate the concentrated hydrogen isotopestream with different hydrogen isotopes from the inlet stream. Thehydron exchange membranes disclosed herein, on the other hand, cancontain the hydrogen isotope to be concentrated in the same isotopicproportion or even in a more concentrated isotopic proportion than foundin the inlet stream. This can provide a technical effect of reducing apotential source of isotopic contamination.

In some embodiments, isotopic water can be present at the surface of, inpores or hydrated to the polymer matrix of the hydron exchange membraneduring operation. Water can facilitate low resistance ionic transport asthe proton transfers from one ionic site to another within the membrane.The water can solvate (hydrate) the ionic groups of the hydron exchangematerial and also can hydrogen bond to other sites within the polymericchain of a given membrane. Water molecules can be characterized by anequilibrium ionization reaction: H₂O→H⁺+OH⁻. This equilibrium of thereaction is heavily weighted towards formation of H₂O; however, aportion of water molecules are always entering or exiting the ionizedstate. Free hydrons and hydroxyl groups in the ionized state canrecombine with hydroxyl groups or hydrons from other water molecules.Thus, a mixture of D₂O and H₂O will over time form all possiblemolecular combinations of H₂O, D₂O, and HDO. Similarly, a mixture of T₂Oand H₂O will form all possible molecular combinations of H2O, T2O, andHTO. A mixture of T₂O and D₂O will form all possible molecularcombinations of T₂O, D₂O, and TDO. Also, a mixture of H₂O, D₂O, and T₂Owill form all possible molecular combinations of H₂O, D₂O, T₂O, HDO,HTO, and TDO. Gas molecules can also take part in this molecularexchange, with hydrogen molecules ionizing and re-combining with ionsfrom water or other gases. The ionization equilibrium reaction of wateris believed to play a role in ionic transport of hydrons between ionicgroups in the hydron exchange membrane, so the presence of hydrogenisotopes in the water at the hydron exchange membrane different than thetarget isotope to be concentrated would appear as a contaminant in thehydrogen isotope output from the apparatus. Accordingly, in someembodiments, water at the hydron exchange membrane can include theisotope(s) of interest at an atomic concentration that is higher thanthe concentration of the isotope(s) found in naturally occurring water.In some embodiments, the water at the hydron exchange membrane caninclude such isotope(s) at an atomic concentration that is greater thanor equal to the concentration of the isotope(s) found in the inletstream to be concentrated. In some specific example embodiments, thewater at the hydron exchange membrane can include deuterons at an atomicpercentage of at least 50%, or at least 90%, or at least 99%, or atleast 99.5%, or at least 99.5% or at least 99.9%, or at least 99.99%,based on the total hydrogen content of the water at the hydron exchangemembrane (i.e., isotopic purity).

FIGS. 2 and 3 show schematic representations of hydrogen concentratingapparatus with provisions for delivery of water to the hydron exchangemembrane. In FIG. 2, isotopic water is delivered to the cathode side ofthe electrochemical cell via a liquid water circulation loop, and inFIG. 3, isotopic water is delivered to the anode side of theelectrochemical cell as water vapor in a humidified inlet stream.In-process delivery of water to the hydron exchange membrane can be donein combination with or as an alternative to pre-treatment of the hydronexchange membrane to incorporate hydrons of the hydrogen isotope intothe hydron exchange membrane.

With reference to FIG. 2, an electrochemical cell stack 32 comprisesmultiple electrochemical cells (not shown) individually comprising ahydron exchange membrane with anode and cathode on opposite sides of themembrane, electrically connected in series. For ease of illustration,internal stack electrical connections and external connection of thestack to a power supply are not shown in FIGS. 2 and 3. Also, anode sidesupply and exhaust manifolds (shown conceptually in FIG. 2 as a singlemanifold 34) direct the inlet stream to the anode sides of the cells inthe stack 32 and remove the outlet (anode exhaust) stream 26. On thecathode side of FIG. 2, a water vessel and pump 40 (pump not shown)pumps isotopic water 38 through line 42 to a cathode side inlet manifoldcomponent of the cathode side manifold 32. Hydrogen isotope gas producedat the stack cathodes bubbles through the isotopic water and formsoutlet stream 44 containing isotopic water and the hydrogen isotope. Inwater a 46, which can be directed to an optional compression and/ordrying stations, represented as 48 in FIG. 2 to produce a final hydrogenisotope outlet stream 24.

With reference to FIG. 3, water is delivered to the hydron exchangemembrane as water vapor in the inlet feed stream. As shown in FIG. 3,the inlet stream 16 is directed to humidifier (also sometimes referredto as a saturator) 38, where it is humidified with isotopic water anddelivered as humidified hydrogen isotope stream 52 to the anode manifold34. On the cathode side, a stream of concentrated hydrogen isotope 54can be optionally dried at drying station 56 to produce a final hydrogenisotope outlet stream 24. In some embodiments, the system of FIG. 3without a liquid water loop can be used as an electrochemical cellcompressor (i.e., electrochemical cell hydrogen pump) to providepressurized hydrogen isotope output gas.

Any water that exits the membrane with the gas phase species of interestcan optionally be removed by conventional methods such including but notlimited to cold trap, adsorbents, membrane or ceramic membranes andfilms, palladium separators, or pressure swing absorption processes(PSA). The reclaimed water can optionally be recycled such as shown withwater recycle stream 49 (FIG. 2) or water recycle line stream 56 (FIG.3). Water recovery and recycle can also be included at numerous otherplaces in the apparatus, such as from the outlet stream 26, inlet stream52 (FIG. 3) where a demister could be used to remove entrained liquidfrom the humidifier 38. Multiple water recovery stages can also be used.For example, the hydrogen isotope gas stream 46 coming off of the watervessel 40 in FIG. 2 could be subjected first to a demister such as acoalescing filter to remove any micro-sized droplets of liquid water,followed by PSA or adsorbent processing to remove water vapor.

The apparatus can also include a controller (not shown) in communication(e.g., via a wired or wireless electronic signal) with the first andsecond electrochemical cell, specifically in communication with thepower supply and with other process control components such as pumps,heat exchangers, pressure control valves, flow meters, temperaturesensors, electrical sensors, and various other components such ascontrol valves such as controlling flow of the feed gas 32 and otherprocess control equipment.

Of course, as mentioned above, the system depicted in the Figures areexemplary, and systems and apparatus according to this disclosure caninclude various other components. For example, multiple electrochemicalstacks can be disposed in parallel and/or multiple second stacks can bedisposed in parallel to provide additional capacity. Multiple stacks canbe disposed in series and/or multiple second stacks can be disposed inseries to provide greater hydrogen isotope pressure outputs and/orpurity. Other modifications and/or additions within the skill of the artcan be made as well. For example, a heat exchanger or enthalpy exchangercan be included to recover heat and/or water from the anode exhauststream 26 and transfer it to the inlet stream 16.

Examples

Tests were performed to investigate isotopic exchange within anelectrochemical pump. The pump and humidifier were pre-treated with D₂Oand used to pump D₂. A mass spectrometer was used to monitor the contentof the pumped gas exiting the cathode compartment. Upon switching fromusing a D₂O pretreated humidifier to a H₂O humidifier a rapid increasein H was observed. This demonstrated how readily isotopes exchangewithin the electrochemical device and supporting sub-systems.

While the this disclosure makes reference herein to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope hereof. In addition,many modifications may be made to adapt a particular situation ormaterial to the teachings herein without departing from the essentialscope thereof. Therefore, it is intended that the disclosure is notlimited to the particular embodiments disclosed herein, but includes allembodiments falling within the scope of the claims.

1. A method of concentrating a hydrogen isotope, comprising delivering afluid comprising the hydrogen isotope to be concentrated and anadditional gas other than then hydrogen isotope to an anode of anelectrochemical cell comprising a hydron exchange membrane comprisinghydrons of the hydrogen isotope, and also comprising said anode on afirst side of the hydron exchange membrane, a cathode on a second sideof the hydron exchange membrane, and an electrical circuit connectionbetween the anode and the cathode; removing a first stream in fluidcommunication with the cathode, the first stream comprising concentratedhydrogen isotope; and removing a second stream in fluid communicationwith the anode, comprising the additional gas delivered to the anodedepleted of the hydrogen isotope.
 2. The method of claim 1, wherein theadditional gas comprises at least one of nitrogen, argon, carbonmonoxide, or carbon dioxide.
 3. The method of claim 1, wherein theadditional gas comprises nitrogen.
 4. The method of claim 1, wherein thehydrogen isotope comprises at least one of deuterium or tritium.
 5. Themethod of claim 1, further comprising delivering water comprising thehydrogen isotope to the hydron exchange membrane.
 6. The method of claim1, comprising contacting the hydron exchange membrane with watercomprising the hydrogen isotope prior to delivering the fluid to beconcentrated to the anode.
 7. The method of claim 1, comprisingdelivering water comprising the hydrogen isotope to the hydron exchangemembrane simultaneous to delivering the fluid to be concentrated to theanode.
 8. The method of claim 1, further comprising recovering orrecycling water comprising the hydrogen isotope.
 9. The method of claim1, further comprising electrochemically compressing the first stream toa pressure greater than atmospheric pressure.
 10. The method of claim 1,wherein the hydron exchange membrane comprises a hydrogen exchangesupport material and water comprising the hydrogen isotope.
 11. Themethod of claim 9, wherein the water comprises a predetermined atomicfraction of the hydrogen isotope.
 12. The method of claim 10, whereinthe predetermined atomic fraction of the isotope is configured toproduce a target hydrogen isotope purity of the first outlet stream. 13.The method of claim 1, further comprising directing water from a watersource comprising the hydrogen isotope to the hydron exchange membrane.14. The method of claim 12, wherein the directing the water from thewater source comprises directing the water to the first side or thesecond side of the hydron exchange membrane via a liquid water flowloop.
 15. The method of claim 12, wherein the water source comprises ahumidifier.
 16. The method of claim 1, further comprising dehumidifyingthe first stream.
 17. The method of claim 1, wherein the hydron exchangemembrane comprises an ionomer.
 18. The method of claim 15, wherein theionomer comprises a fluoropolymer comprising sulfonate groups.
 19. Amethod of concentrating a hydrogen isotope, comprising delivering afluid comprising the hydrogen isotope to be concentrated and nitrogen toan anode of an electrochemical cell comprising a hydron exchangemembrane comprising hydrons of the hydrogen isotope, and also comprisingsaid anode on a first side of the hydron exchange membrane, a cathode ona second side of the hydron exchange membrane, and an electrical circuitconnection between the anode and the cathode; removing a first stream influid communication with the cathode, the first stream comprisingconcentrated hydrogen isotope; directing the first stream to a watervessel and separating the concentrated hydrogen isotope from the anisotopic water in the water vessel; after the separating, directing theconcentrated hydrogen isotope to a compression and drying station toform a final hydrogen isotope outlet stream; directing the isotopicwater from the water vessel and a separated water stream from thecompression and drying station to the second side; and removing a secondstream in fluid communication with the anode, comprising the nitrogendelivered to the anode depleted of the hydrogen isotope.
 20. A method ofconcentrating a hydrogen isotope, comprising delivering a fluidcomprising the hydrogen isotope to be concentrated and nitrogen to ananode of an electrochemical cell comprising a hydron exchange membranecomprising hydrons of the hydrogen isotope, and also comprising saidanode on a first side of the hydron exchange membrane, a cathode on asecond side of the hydron exchange membrane, and an electrical circuitconnection between the anode and the cathode; removing a first stream influid communication with the cathode, the first stream comprisingconcentrated hydrogen isotope; directing the first stream to a dryingstation to form a final hydrogen isotope outlet stream and a separatedwater stream; combining the fluid with the separated water streamupstream of the anode and humidifying the stream; and removing a secondstream in fluid communication with the anode, comprising the nitrogendelivered to the anode depleted of the hydrogen isotope.